400 MZ-B/Powerdynamo

[brian kirby]

On the Penton Racing application list, the PVL for all the Pentons/KTMs with KTM 125 engines up to '97, 250s up to '86, 420/440/500/550 is 40360. The MZ-B/Powerdynamo for the 250 and smaller engines is 70060, and the 400-larger is 70177. Obviously the crank taper is the same between them all since the PVL number is the same, does anyone know what the difference is in the 70060 and 70177 MZ-B/Powerdynamo? Does it hopefully have a heavier flywheel? I really really need a heavier flywheel for the '77 MC5 400, and I suppose I could get the big "enduro" Motoplat flywheel, but I would really rather have a new ignition.

Brian

[Andreas Piepke]

Hi Brian,

I don't want to state the obvious and if I do please disregard this message. Powerdynamo is a German manufacturer of ignition systems. They have a web site and their KTM components are listed under:
http://www.powerdynamo.biz/deu/systems/lists/ktm.php
It seems they offer one system that fits most types of vintage KTM/Penton motorcycles. The part number is 76 10 799. Are your part numbers for components no longer distributed? Their web site, unfortunately, seems to come straight from Google translator. You could send them an email if you have a specific question regarding possible rotor alternatives. I can translate it to German for you if you want.

Andreas

[Jerry Birky]

The only difference between the PVL kit # 70060 (250cc&less) and PVL kit # 70177 (open class engines) is the stator. The stator supplied with the 70177 kit has a 5000 wind stator. This stator generates AC voltage at a lower rpm. Since open class bikes have more compression and are harder to kick start, they need to spark as soon as possible.
The trade off is the timing curve, the 4000 wind stator is more suited to a higher revving engine such as 125 or 250. PVL rotors weigh just 11 oz. the Penton weight will add another 17oz.
The reason the Power dynamo has only one version for all the early KTM engines(76 10 799 00) is they have a flat timing curve & generate voltage at low rpm. The Power Dynamo rotor weighs 24 oz.

[brian kirby]

OK, thanks for the explanation Jerry. Is there a possibility that you might create an add on flywheel wight for the Powerdynamo external rotor like they make for modern flywheels?

Brian

[Jerry Birky]

Hi Brian,
   We currently do not have a bolt on weight for the 24oz. Power Dynamo flywheel. We can special order this ignition kit with a 51oz flywheel that features a 13 oz. removable weight. This will give you the choice of having both a 38 & 51oz flywheel.

[brian kirby]

Excellent!

Brian

[Larry Perkins]

51 oz. will calm that 400 down Brian!